Luminous display



J. C. STIMSON Aug. 25, LUMINOUS DISPLAY 0R REFLECTOR SIGN Re.

Original Filed July 9, 1923 3 Sheets-Sheet 1 mam Jiwar/mm 0577mm.

J. C. STIMSON N Re. 18,166

Aug. 25, 1931.

3 Sheets-Sheet 2 Original Filed July 9, 1925 J. C. STIMSON A 25 1931 LUMINOUS DISPLAY 0H REFLECTOR SIGN R 18 166 Original Filed July 9, 1923 3 Sheets-Sheet 3 {A M AvAv/ Q 4 1 .113-

fi m m Z; 70/r/m/n/r 6357mm Reissued Aug. 25, 1931 UNITED STATES PATENT OFFICE :roumm c. s'rmson,

or omcaeo, mime L'UMIHOUS DISPLAY B- REI'LEOTOB SIGN This invention relates to luminous displays, and more particularly to luminous display or reflector signs.

In the accompanying drawings:

Figures 1 and 2 are a side elevation and a plan view respectively showing an illustrative luminous display or reflector sign embodying this invention;

Figure 3 is a plan showing another embodiment of this invention;

Figures 4 and 5 are views illustrating the principles of operation of a reflector used in the luminous display sign embodying this invention;

Figure 6 is a erspective view of a prismatic plate used in the display sign;

Figures 7 8 and 9 show different applications of the reflector or prismatic plate in the formation of display characters on the luminous display or reflector sign embodying this invention;

Figures 10, 11 and 12 are enlargements of portions of Figures 7, 8, and 9 respectively, showing the reflecting units forming the out- 2 line of the character.

Display signs as heretofore made are of two general t p es, namel those in which the light is radiated from i amps forming the display characters of the sign, and those in which the characters are displayed by diffuse reflection from the surfaces of the character on the si n area.

\Vhere the light is radiated directly from the lamps forming the characters, only a small part of the total emitted light is useful; for only a small percentage of the total emitted light from a bulb or a series of bulbs is utilized for display purposes, keeping in mind that the light from a. bulb is radiated in a sphere of which the source forms the center and that the useful light for display purposes forms only a small sector of the sphere. Accordingly since the intensity of the illumination varies inversely as the square of the distance, it necessarily follows that in order to obtain a practical range of visibility, bulbs of relatively high candle power must e used.

Not only is a display sign employing bulbs for direct radiation wasteful in energy, but the maintenance cost in the replacement of I actors being built up by spaced 850,403, filed July 9, 1923. Application for reissue Serial No. 644,649.

bulbs and repairs generally is also hi h, especially since in order to secure a disp ay of given characters, these characters must be built u by a series of lights requiring a multiplicity of bulbs.- Moreover such charoint sources of light can only approximate tlie outline of the character, and require high power lamps to make them visible at a distance. Such signs are, moreover, very expensive to install and operate.

In luminous display signs in which the sign area is painted or formed to provide displa characters which are illuminated by directing lightfrom a suitable source or sources onto the sign area, the characters are visible by diffuse reflection. Such reflection fills the entire hemisphere in front of the si although serving a useful pur use within only a small zone. By reason 0 the nature of the surface of such a sign a lar part of the light is absorbed, even when t e sign is painted with ordinary paint. In order to avoid high lights, flat paints are sometimes used resulting in a matte surface. From such a surface the light is even more fully diffused and there is a greater absorption of light. As a result the sign, in proportion to the amount of illumination used is effectively visible at short distances only. Further, even at short distances such signs lack the brilliance of electric signs.

One of the objects of this invention, therefore, is to provide means of creating luminous display or reflector signs in which the light directed on the sign area and more particularly on the display characters, is so emitted or reflected as to be confined within a selected field from which the dis la characters are visible; this is accomplished in the illustrated embodiments of this invention by reflecting the light from the display characters in the form of a spreading beam or beams into that selected, visible field.

Another object of this invention is to pro- 95 vide a luminous display or reflector sign having dis lay characters visible from within a selecte field, whereby the light emitted from the characters is confined within that field;

this is accomplished in the illustrated embodiments of this invention by providing the characters with reflecting surfaces which are constructed and arranged to reflect the light impinging thereon in the form of a spreading beam or beams and into that selected visible field in order to display the characters within that field.

Further objects will appear from the detail description taken in connection with the accompanying drawings.

Generally stated and in accordance with this invention the luminous display or reflecting sign has a sign character or characters provided with or formed of reflecting units arranged to form the outline or outlines of the character or characters, each of these units has a reflecting area adapted to reflect light incident thereon from a distant" source back in the general direction of the light source, and the units have means or are constructed to slightly spread the reflected light. The reflecting units are usually arranged along the strokes of the character to outline the same. These units may be arranged in clusters along the character. In accordance with an illustrative embodiment of this invention the reflecting surfaces forming the characters of the luminous display or reflector sign are in the form of triple reflectors constructed as shown and described in Patent No. 1,671,086, issued May 22, 1928.

A tri )le reflector comprises three reflecting sur aces arranged to intersect at a common point and such a reflector has the property of reflecting incident beams back to their source irres ective (within limits) of the angle of incicliance of such a beam with respect to the axis. \Vhere the triple reflector is a prism causing reflection of the incident beam, the limitin angle of incidence (with respect to the axis) can be increased while the loss of reflected rays is decreased for any given angle of incidence. While, however, in a central reflector (in which the reflecting surfaces are at right angles to each other so as to form in effect the corner of a cube and which is provided with optically plane surfaces) the incident beams are reflected directly back to the source, the triple reflector described and shown in the patent referred to is so constructed as to reflect the impinging light in the form of a spreading beam or beams. This is accomplished in an embodiment of the invention described in the patent referred to, by deviating the reflecting surfaces thereof slightly from true right angular relation and by distorting the surfaces, so as to vary from the true optical surface of a central reflector; specifically stated this latter is accomplished in a prismatic reflector by forming the reflector of pressed glass and by so controlling the degree of polish of the reflecting surfaces as to leave the same sufficiently rough and undulating to secure spread reflection This is illustrated in Figures 4 and 5, where the surfaces of the triple reflector 12 are shown undulating (on an exaggerated scale) so that an incident beam 13 from a source of light 14 provided with a reflector 15 (such as a parabolic reflector) is reflected in the form of a spreading beam which is of uniform intensity, the spread of the beam being controlled by the degree of polish given the reflecting surfaces.

As a practical illustrative embodiment a reflecting area is formed by a prismatic plate 17 of presesd glass, which has formed on the back thereof a series of triple reflecting prisms 18 arran ed in continuous relation, th reflecting surfaces of these prisms being formed by pressing in a suitable mold and the polish of the reflecting surfaces being controlled by the degree of polish given the mold surfaces. Such a prismatic plate has the property of reflecting incident substantially parallel beams of light back past the source in the form of a cone having the platc as the apex of the cone and the source of light in the axis of the cone, regardless of the position of the light source with respect to the reflector within wide angular limits. If the reflecting plate is transparent, reflection takes place through total internal reflection. the angular range through which the transparent total triple reflecting prisms function being suflicient for mostdisplay signs. If service conditions require an angular range and quantity of reflection beyoml the reflecting range of the transparent primatic plate, the back or figured face of the plate may be silvered, thus widening the range through which all of the units of the reflector will function.

The application of the reflecting prism to luminous display or reflector signs can be varied to suit requirements. Thus as shown in Figures 7 and 10, the characters 19 may be formed of pressed glass having formed on the back thereof a series of triple reflecting prisms whose reflecting surfaces arc formed as heretofore described. 'l'hcsc characters may either be used integrally or may he built up of pa rts, and such characters, or the parts thereof may be secured to a sign area in any suitable manner, it being understood. of course, that these prisms will project from the rear part of the character.

As shown in Figures 8 and 11, and S) and 12 the sign area 20 or 21 may be formed of a prismatic plate, either in a single piece or built up from a series of plntcs, with the rcflectin surfaces formed as hcretoforc dcscribed and with the triple reflecting prisms on the back of the sign area. The characters 22 or 23 may then be formed either by coating the sign area, leaving the outlines of the characters exposed as shown in Fi 'urcs 8 and 11 or by coating the characters u-aving the back-ground exposed as shown in Fi ures 9 and 12; in the first case, Figures 8 an 11, the characters will appear illuminated while in the second case Figure 9, the background will appear illuminated. It will be understood, of course, that any suitable opaque paint or other coating may be used and this coating may even be translucent and in var ing colors so as to present a varied color isplay. It will, of course, be understood that the total sign area need not be formed as a reflecting surface in either case but only such portions as are required. With this form of sign area the display characters may be varied by removal of the coating and by the application of a new coating.

Figures 1 and 2 show the application of this mvention to a location. The frame of the sign 1 is provided with a sign area 24, which is constructed in any manner as heretofore described while the light is directed on the sign area and the display characters thereon from a suitable source, such as one or more'lamp bulbs and a reflector 25 which is arranged to project the light on the sign area and the display characters. Any suitable reflector of a high concentrating type, such as a parabolic reflector or a recently developed compensating Mangan mirror may be provided. Such a spot-light is so constructed and arranged as to throw a spreading beam in order to just cover the sign area and the display characters thereon. From the principles of the reflector as heretofore described, it will be readily seen that the light will be reflected from the display characters in the form of a spreading beam or beams and into the selected field (which is, in this case, along the street or thoroughfare 4), which field is that from which the luminous display is visible. It will be understood, of course, that the source of light and the impinging reflector 25 and the sign area are so relatively positioned and with respect to the visible field, and that the spread of the beam is controlled as heretofore described, as to confine the reflected light within the visible field. Accordingly maximum efliciency and maximum visi ility and brilliance will be obtained with a minimum of current consumption. It will, of course, be understood that a lamp of sufficiently high candle power and a reflector of a suflicient size will be small relative to the sign area so that the sign area and the characters thereon will not be obscured by the presence of the source within the reflected beam; as a ractical proposition the light projecting re ector 25 will really be invisible at a comparatively short distance from the sign area.

Occasionally a sign is favorably located in a position where it may be viewed without obstruction over a large territory. Such a location may be secured on the top of a high building facing an open public square or at the intersection of wide avenues forming an acute angle. Such a location is shown in Figure 3 where the frame of the sign 1 containing the sign area 24 constructed as heretofore described is located on top of a building 26. In order to secure a distributed field, two or more spot-lights 27 and 28 are located to face the sign area, as by mounting the same on buildings 29 and 30 respectively. The spot-light 27 can be arranged so as to direct a beam 31 on the sign area, which beam will be reflected in the form of a spreading beam 32, while the beam 33 from the spot-light 28 is reflected in the form of a spreading beam 34. The elements may be so constructed and relatively arranged as heretofore described, that the light will be reflected from the display characters in the form of spreading eams into the selected visible field, the light from the display characters and incident from the several sources being reflected into selected adjacent visible field areas so as to confine the light reflected from the sign area and the display characters thereon within the visible field. By thus suitably arranging a series of spot-lights and by suitably constructing the sign area and the reflecting surfaces, any desired field of vision may be covered, but the light emanating from the character is confined within that field.

It will, therefore, be seen that the invention accomplishes its objects, for in accordance with this invention the light emitted from the sign area and the display characters thereon is limited and confined within the visible field. Accordingly the emitted light is transmitted where it will be observable, while it is excluded from outside spaces. It will, therefore, be seen that maximum efliciency is secured even with the losses incident to the employment of reflectors and refractors. Not onl is the cost of installation low, but the malntenance cost is low for the reason that the sign area is rugged and will not deteriorate. Nor will the efliciency be impaired on account of the ex osure to weather for the reason that the re ecting surfaces are in the rear where they can be protected. Where silvered plates are employed the reflectors may be sealed to the sign board or similarly treated so as to protect them from the weather. If transparent total reflecting plates are used little rotection is necessary. It is to be noted in this connection that dust particles, if not in optical contact with the reflecting surfaces, will not impair the reflection but optical contact can readily be avoided by protecting the back against rain. The display sign is so constructed that any suitable characters in the form of letters, figures, illustrations and trade marks may be emplo ed with-. out resorting to block characters. oreover any suitable color effect may be obtained as heretofore described by suitable coating applied to the sign area. A desired color effect may also be secured by introducing a color screen in the path of the beam from the spotlight or by passing a varied color screen therei hrough. Elaborate flashing effects may also be secured by simply moving an opaque screen in the path of the beam from the spotlight, or by moving one containing perforations designed to secure the desired effect, or by using a semi-transparent screen containing gradations of shading. I urthermore the sign area may be converted and changed readily as heretofore described without great ex ense.

Vhile a number of embodiments of this invention have been described and illustrated in an illustrative environment, it will be understood that this invention is susceptible of various embodiments and in various environments in the general art of reflecting signs to perform their useful functions in those environments. It is further obvious that various changes may be made in details without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to the specific details shown and described.

Having thus described the invention, what is claimed is:

1. A luminous display sign comprising, a reflecting area on which characters are dis played so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of reflecting surfaces formed and positioned to cause a definite spread of the reflected light from said area and so as to confine the reflection within the selected field, in order that the characters may be visible to an observer anywhere within that field.

2. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of a series of reflectlng units arranged in contiguous relation and constructed and positioned to cause a definite spread of the reflected light therefrom and so as to confine the reflection within the selected field, in order that the characters ma 1 be visible to an observer anywhere within that field.

3. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of a series of reflecting units arranged in contiguous relation, each of said units bein constructed to direct a definite spreading beam of substantial uniform intensity into the select ed field, and the composite beam from the several reflecting units being confined within the selected field, in order that the characters may be visible to an observer anywhere within that field.

4. A luminous disnlav sign comprising, a reflecting area on which characters are displayed so to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said are-.1 for reflection within a selected field, said reflecting area being composed of a series of reflecting units arranged in contiguous relation, each of said units having reflecting surfaces constructed to direct a definite spreading beam into the selected field and having means for distributin the reflected light uniformly throughout the field of spread, and the composite beam from the several reflecting units being confined within the selected field, in order that the characters may be visible to an obscver anywhere within that field.

5. A luminous display sign comprising, a ieflecting area on which characters are displayed so as to be visible in front of said area, and a series of light sources in front of and distant from said area ada )ted to direct the light from said area for rcf'fection within selected adjacent fields, said reflecting area being composed of reflecting surfaces formed and positioned to cause a definite spread of the reflected light from said area and so as to confine the reflection within the selected fields, in order that the characters may be visible to an observer anywhere within those fields.

6. A luminous display sign having display characters visible from Within a selected field, and a light source in front of and distant from said characters, said characters having reflecting surfaces arranged in relative angular relation to multiply reflect light impinging thereon back towards the light source in the form of a spreading beam or beams, said reflecting means being adapted to direct the ieflected light into and confine the same to said field in order to display said characters within said field.

7. A luminous display sign having display characters visible from within a selected field, and a light source in front of and distant from said characters, said characters being formed by total reflecting prisms whose surfaces are arranged in angular relation to multiply reflect the light in the form of spreading beams into and confined within the selected field.

8. A luminous display sign having display characters visible from within a selected field, and a light source in front of and distant from said characters, said characters being formed by triple reflecting surfaces which deviate from their true right angular relation adapted to reflect the light into and withiri iihe selectectll field. h d

9. uminous is is si avin isplay characters visible fii'on i v iizhin a selected l field, and a light source in front of and distant from said characters, said characters being formed by triple reflecting surfaces ada ted to reflect light impinging thereon bac towards the light source, and means cooperating with said surfaces adapted to sligntlv spread the reflected light to a definite degree in the form of a spreading beam or beans so as to confine the same within said fiel 10. A luminous display sign havin dislay characters visible from within a se ected fleld, and means in front of and distant from said characters for directing light indiscriminately on said characters, said characters having triple reflectors whose reflecting surfaces deviate "from their true right angular relation adapted to reflect the light impingin thereon so as to confine the same within said field.

11. A luminous display sign havin display characters visible from within a se ected field, and means in front of and distant from said characters for directing light from a source on the display characters, said characters being reflectin surfaces arranged in relative angular relatlon to multiply reflect the light impinging on said displa characters back towards said source, an means coo crating with said surfaces adapted to slig tly spread the reflected light to a definite degree in the form of a spreading beam or.

beams into said field.

12. A reflecting sign having a sign character provided with reflecting units arranged to form an outline of the character, each of said units havin a reflecting area ada ted to reflect light incident thereon from a istant source back in the general direction of the light source and having means adapted to slightly spread the reflected light.

13. A reflecting sign having a sign character provided with reflecting units arranged along the strokes of the character, each of said units having a reflecting area adapted to reflect light incident thereon from a distant source back in the general direction of the li ht source and having means adapted to slight y spread the reflected light.

14. A reflecting sign having a sign character provided with clusters of reflecting units arranged to form an outline of the character, each of said units having a reflecting area adapted to reflect light incident thereon from a distant source back in the general direction of the light source and aving means adapted to slightly spread the reflected light.

15. A reflecting sign having a sign character provided with clusters of reflecting units arranged to form an outline of the charaeter, each cluster being composed of a series of units arranged in contiguous relation, each of said units having a reflecting area adapted to reflect li' ht incident thereon from a distant source ack in the general direction of the li ht source and having means adapted to slig tly spread the reflected light.

16. In a reflecting sign, the combination with a reflecting area consisting of a number of prisms, whose opposite sides meet at substantially ri ht angles at their apiece and which are a apted to reflect 1i ht incident thereon from a distant source ack in the general direction of the light source and which have means adapted to slightl spread the reflected light, of means for bloc ing out portions of the reflecting area to form a de- SlgIl.

17. In a reflecting sign,.a siggle plate of glass having on one side a re ecting area. consisting o a number of prisms, whose opposite sides meet at substantially right angles at their apices and which are adapted to reflect Ii ht incident thereon from a distant source ack in the eneral direction of the light source and WhlCh have means adapted to slightly spread the reflected li ht, said plate having on its other side means or blockmg out portions to form a design.

18. In a reflecting sign the combination with a reflecting area consisting of a number of substantially right angled tetrahedra, said tetrahedra adapted to reflect 1i ht incident thereon from a distant source bac in the general direction of the light source and having means adapted to slightly spread the reflected light, of means for blocking out portions of the area to form a design.

19. In a reflecting sign, the combination with a reflecting area consisting of a sheet of plate glass on which are formed a number of prisms whose o posite sides meet at substantially right ang es at their apices and which are adapted to reflect li ht incident thereon from a distant source %ack in the general direction of the light source and which have means ada ted to slightly spread the reflected light, 0? means for blocking out portions of the reflectin area to form a design.

20. In a re ecting sign, the combination with a reflecting area consisting of a sheet of plate glass on which are formed a number of substantially right angled tetrahedra, said tetrahedra adapted to reflect li ht incident thereon from a distant source ack in the general direction of the light source and havin means adapted to slightly spread the re ected light, of means for blocking out portions of the reflecting area to form a design.

21. In a reflecting sign, a plate of glass having on one side thereof a plurality of tetrahedral prisms, said prisms adapted to reflect light incident thereon from a distant source back in the general direction of the liubt source and having means adapted to slightly spread the reflected light, said plate having on its other side an opaque coating disposed to block out a sign substantially as and for the purpose described.

In testimony whereof I aflix my signature this 13th day of June, 1931.

JONATHAN C. STIMSON.

CERTIFICATE OF CORRECTION.

Reissue Patent No. 18,166. Granted August 25. 1931 to JONATHAN G. STIMSON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 80, for "continuous" read contiguous. and line 81, for "th" read the; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of September, A. D. 1931.

M. J. Moore. (Seal) Acting Commissioner of Patents. 

